Small joint manipulation - credible threat or gimmick excuse?

I have been discussing aspects of BJJ with a women's self-defense instructor (not my idea), and our conversations are typically very awkward and bizarre. I was describing a guillotine choke earlier (to explain why my neck hurt), and the instructor decided to illustrate how a guillotine would be handled in the context of self-defense. Now at that point all I had explained was that a headlock type of hold was involved, and the counters that were listed to me included: punch to the balls (which caused me to blurt out "yeah, good luck with that"), elbow to the solar plexus (chalk that up to me not explaining thoroughly), and small joint manipulation.

Obviously those strikes are not viable escapes. But small joint manipulation, for instance breaking a pinky finger to loosen a hold - I wonder, is that a serious threat to a BJJ player? I hope someone with experience can comment on this.

From my admittedly non-expert perspective, it seems like there are many situations where a superior grappler can control one or both of a person's arms without exposing their fingers, but it seems credible that some positions or subs might expose the fingers. I think it was on submissions101.com that they suggested that when you try to apply an RNC in a streetfight, you ball your hands into fists once the choke is in, to protect your fingers.

Does anyone have anything more solid than speculation to add to this?

"[Fighting for Points] is doubtless very pretty, and invariably draws applause, but preferences should always be given to blows that do some business, to good straight hits that do something toward finishing the fight.
A man who has carefully trained for brilliant tapping play, will find himself considerably out of it in case he is called upon to do any real work."
-A.J. Newton, Boxing.

There's a wristlock that can get you out of a standing guillotine depending on how the choker grabs his own wrist, but once the choker falls back and puts the chokee in guard, the chokee is pretty fucked.

In other self defence applications: r34l fights are highly chaotic. It is possible that twisting a pinky could put an opponent at your mercy, it is possible that the opponent is so hyped up on adrenaline that ripping the pink off all together would barely be noticed.

Small joint stuff is good for controlling someone when body contact is not wanted. For example if I was controlling a drunk/nutcase I would not really want to be close to them.

Pinning them to the floor or getting a nice tie up on them would work well to move them around (better than small joint manipulation) BUT I don't want to have body on body contact with a nutjob.

You can use a wristlock and stuff to keep them controlled and at a distance.

As far as being attacked with them from a BJJ standpoint? There are more effective ways to get out of chokes but yes they would help along the way. I wouldn't use them standalone. For example posturing out of a triangle could be helped by hitting the groin once you have made some space using good BJJ position/escape work.

Is it feasible to use finger breaks to escape various BJJ subs or pins? Is it worth training finger breaks and defenses in addition to BJJ? If so, where does one find credible instruction in something like that? What are some tactics you can use in BJJ to make yourself proof against finger attacks?

"[Fighting for Points] is doubtless very pretty, and invariably draws applause, but preferences should always be given to blows that do some business, to good straight hits that do something toward finishing the fight.
A man who has carefully trained for brilliant tapping play, will find himself considerably out of it in case he is called upon to do any real work."
-A.J. Newton, Boxing.

Is it feasible to use finger breaks to escape various BJJ subs or pins? Is it worth training finger breaks and defenses in addition to BJJ? If so, where does one find credible instruction in something like that? What are some tactics you can use in BJJ to make yourself proof against finger attacks?

1) If the sub is already locked on then probably not, but if you can intercept and isolate a finger or two before the sub sinks in, then yes (depending on the the sub). Even if the other guy is so hyped up he can't feel the pain, it's impossible to grip strongly with broken fingers.

2) It's not worth training finger breaks for BJJ/MMA competition because small joint manipulations are not allowed under the rules. IMO it is worth training such techniques for street fighting/life and death combat.

3) Some classical jujitsu ryu-ha offer codified finger-breaking techniques. The "Small Circle" style, founded by Professor Wally Jay, is probably best known for specializing in these techniques.

4) Grip strength exercises like squeezing rubber balls might buy you the second or so you'd need to resist the attempted finger break and sink the sub on, but it mostly comes down to positioning and circumstance (sweaty hands, etc.) If someone successfully isolates your little finger and applies sharp pressure in the right direction, he'll probably break it.

Finger locks are used in CMA to get a better control on something like the elbow or shoulder generally. They are not necessarily holds or breaks by themselves.

I've heard fingers are harder to actually break than they seem. One of the more destructive ways to attack the fingers I've seen is to get a hold on a finger, then attack the base of that finger with a hard edge of the hand strike (generally, you're attacking the pinky or inddex finger and trying to break it sideways instead of backwards). I sometimes work this into slow clinch work, but never at full speed. I think they work okay if you don't fixate on them or put yourself in bad positions to do this (something I often see in finger and wrist lock stuff).